* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f8f9fa;
    color: #333;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: opacity 0.3s;
}

nav a:hover {
    opacity: 0.8;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.product-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.product-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.product-info {
    padding: 1.5rem;
}

.product-name {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #333;
}

.product-description {
    color: #666;
    margin-bottom: 1rem;
    line-height: 1.4;
}

.product-price {
    font-size: 1.3rem;
    font-weight: bold;
    color: #667eea;
    margin-bottom: 1rem;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    opacity: 0.9;
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-danger {
    background: #dc3545;
    color: white;
}

.form-container {
    max-width: 500px;
    margin: 2rem auto;
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #333;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e9ecef;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
}

.cart-items {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.cart-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid #e9ecef;
}

.cart-item:last-child {
    border-bottom: none;
}

.cart-total {
    text-align: right;
    margin-top: 2rem;
    font-size: 1.5rem;
    font-weight: bold;
    color: #667eea;
}

.quantity-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.quantity-btn {
    width: 30px;
    height: 30px;
    border: none;
    background: #f8f9fa;
    border-radius: 50%;
    cursor: pointer;
    font-weight: bold;
}

.quantity-btn:hover {
    background: #e9ecef;
}

.hidden {
    display: none;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-info span {
    font-weight: 500;
}

.logout-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
}

.logout-btn:hover {
    background: rgba(255, 255, 255, 0.1);
}

/* 响应式设计 */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        gap: 1rem;
    }
    
    nav ul {
        gap: 1rem;
    }
    
    .products-grid {
        grid-template-columns: 1fr;
    }
}